I do keep seperate address book groups: Great renters I want back, inquiries that I've verified, but was unable to accomodate , etc. I do it as I go along, so I can send out a simple newsletter type email.

You can manually enter your reservations into ReservationManager (instructions here), but not inquiries (as those are automatically created via the HomeAway inquiry system). If you manually enter a reservation, you can mark it "tentative" so it doesn't block the calendar until you confirm the booking.